Electric motor and brake.



No. 736,461. PATENTED AUG. 18, 1903. A. A. THRESHER.

ELECTRIC MOTOR AND BRAKE.

APPLICATION FILED JUNE 17, 1903.

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PATENTED AUG. 18

A. A. THRESHERi ELECTRIC MOTOR AND BRAKE.

APPLICATION FILED JUNB17, 1908.

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iatented August 18, 1903.

PATENT OFFICE.

ALFRED A. THRESHER, OF DAYTON,.OHIO.

ELECTRIC MOTOR AND BRAKE.

SPECIFICATION forming part Of Letters Patent NO. 736,461, dated August18, 1903.

Application filed June 17,1903. Serial No. 161.923. (No model.)

To on whom it may concern.-

Be it known that l, ALFRED A. 'lHREsHER, of Dayton, in the county ofMontgomery,

State of Ohio, have invented certain new and useful Improvements inElectric Motors and Brakes; and I do hereby declare the following to bea full, clear, and exact description of the same, reference being had tothe accompanying drawings, forming a part of this specification, and tothe letters of reference marked thereon.

- This invention relates to improvements in brake mechanism for electricmotors-such, for instance, as are used in ammunition-hoists, &c.where itis necessary or desirable that the load shall be held if theactuating-current fails or the motor becomes inoperative for any cause.

The invention consists in certain novel details of construction andcombinations and arrangements of parts, all as will be now described,and pointed out particularly in the appended claims.

In the accompanying drawings, Figure 1,is a vertical section through amotor embodying the present improvements, certain details of the motorportion of the structure being omitted, as they form no part of thepresent invention. Fig. 2 is a detail section taken through the shaft atright angles to Fig. 1. Figs. 3, 4, and 5 are detail elevations,respectively, of one .head of the motor, the clamping-disk, andbrake-wheel. Fig. 6 is an end elevation of the motor, dotted linesshowing the brake-release magnets and drive-gearing. Fig. 7 is a sectioncorresponding to Fig. 2, but showing a different arrangement of themagnet.

Similar letters of reference in the several figures indicate the sameparts.

The motor illustrated is of the inclosed type, having a casing A, towhich the polepieces B are connected, and heads C, secured to the endsof the casing, preferably by bolts 0. The heads support or have formedtherein bearings for the shaft D, which latter carries the armature (Zand commutator E, both of ordinary or preferred construction. Thebearings for the shaft have oil-reservoirs F therein, and a suitablemeans, such as a ring traveler f, for carrying the oil to the top of theshaft as the latter is rotated.

Between one of the heads, preferably the head remote from the commutatorand the armature, there is a brake-wheel or disk G keyed on the shaft,so as to have a limited movement longitudinally of the shaft. The peripheryof this brake-wheel or disk is formed with a frusto-conical orinclined frictionsurface 9, adapted to cooperate with a reversely-inclined surface or friction-bearing H, which may be directly onthe casing, but is preferably on a separate ring or annular frame H,clamped between the head and casing, as will presently appear. A secondfrusto-conical or inclined friction-surface g on the opposite side ofthe wheel or disk Gr cooperates with a similar surface h on aclamping-disk H preferably mounted on the head of the motor, so as to beheld against rotation, but so as to be capable of a bodily movementlongitudinally of the shaft. The clamping-disk may be mounted on acentral hub of the head and is held against rotation by a lug 1, adaptedto enter a slot or slotted wing I on the disk.

The clamping-disk is advanced to clamp the brake-wheel between it andthe inclined surface on the casing by spring-pressure and preferably bya multiplicity of springs K, Figs. 1 and 3, located in sockets orrecesses in the head and bearing directly against the clamping-disk.

The clamping action of the disk under the influence of the springs issufficient to arrest the motion of the armature-shaft and to hold thesame stationary against the weight of the load. Thus the shaft may besaid to be normally held by the brake, and in order to release the samean electro magnet or magnets is or are formed on the head, preferably byrecessing said head for the reception of a coil or coils M, Said magnetsact 011 the disk in opposition to the force of the springs and arepreferably controlled by the working current for the motor, either adirect or a shunt circuit being employed.

I11 the construction of Figs. 1 to 6 two coils M are employed, one oneach side of the center of the head, thereby forming a strong magneticcircuit, with the body of the head as a base and the projecting portionsof the head inside and outside the coils as the pole pieces for actingon the clamping-disk; but

it is obvious that for some purposes it may be desirable to use magnetsof different specific constructionas, for instance, a single coil. Thismay be done by forming an annular recess in the head, extending aroundthe armature-shaft, as shown, for instance, in Fig. 7, where the coil isindicated by the letter N. In any instance it will be seen that themagnets are on the interior of the end head or closure for the motor,together with the brake-wheel and clamping-disk. The frusto-conical orinclined face form of the friction-surfaces greatly increases the powerof the brake, the wheel being wedged between two surfaces instead ofbeing simply pressed against one surface or clamped between two surfacesextending in planes at right angles to the axis of rotation.

The whole structure is exceedingly simple and compact, and the motor,together with its brake mechanism, presents a similar appearance,occupies practically the same space as and is protected against injurysimilar to an ordinary motor without a brake mechanism.

By forming the fixed friction-surface as a ring separate from the casingit may be readily adjusted or renewed and, what is of greaterimportance, it may be clamped to the head-as, for instance, by the boltsQ and csome of which may extend only into the ring and others extendthrough the ring and into the casing to hold the head and brake in place. Thus by loosening the bolts which hold the head in place the wholehead, brake, and attached parts may be removed as a body to gain accessto the motor. \Vith such construction the removal of the head does notnecessitate the separation or change in adjustment of the brakemechanism, as would be the case if the fixed friction-surface wereformed integral with the casing.

The power .from the armature shaft is preferably transmitted through aspur-gear O to a gear-wheel P, mounted on a shaft Q, journaled inhearings on the side of the motor-casing and from the latter to themechanism to be driven.

Obviously the circuit for the brake may be controlled independently ofthe motor itself without departin from the invention; but the parts aredesigned more especially for use in connection with a motor which mustbe automatically controlled should the current be shut off or the motorbecome accidentally injured, so as to interrupt the application of itspower.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is I 1. The combination with an electricmotor, its shaft and inclosing casing embodying heads having bearingsfor the shaft, of a brake-wheel on the shaft between the heads, asurface with which said wheel cooperates, a spring for effectingengagement between the wheel and itscooperating surface and anelectromagnet for holding the same out of ras es;

such engagement against the tension of the spring; substantially asdescribed.

2. The combination with an electric motor, its shaft and inclosingcasing embodying heads having bearings for the shaft, of a brake-wheellongitudinally movable on the shaft between the heads, a fixedfriction-surface with which said wheel cooperates, a spring for movingthe wheel longitudinally of the shaft and into contact with its cooperating fixed friction-surface and an electromagnet for holding the wheelout of engagement with said cooperating surface; substantially asdescribed.

3. The combination with an electric motor, its shaft, armature andinclosing casing embodying heads having bearings for the shaft of amagnetically-releasedfriction-brake for the shaft located between thearmature and one of the heads of the casing; substantially as described.

4. The combination with an electric motor, its shaft, armature andinclosing casing embodying heads having bearings for the shaft, of a1nagnetically-released friction-brake for the shaft located between thearmature and one of the heads of the casing and an electromagnet forreleasing the brake located on the head and controlled from themotor-actuating circuit; substantially as described.

5. The combination with an electric motor, its shaft, armature andinclosing casing embodying heads having bearings for the shaft, of afriction brake wheel mounted to move longitudinally of the shaft andbetween the armature and head of the casing, a fixed friction-surfacewith which the wheel cooperates, a clamping-disk between the wheel andhead, springs acting on the disk to move the wheel into engagement withits cooperating fixed friction-surface and an electromagnet in the headfor moving the disk against the tension of its springs to release thewheel; substantially as described.

6. The combination with an electric motor, its shaft, armature andinclosing casing embodying heads having bearings for the shaft, and aninclined fixed friction-surface, of a clamping-disk movablelongitudinally of the shaft and having an inclined friction-surface,springs for moving said disk in one direction, an electromagnet formoving the disk against the tension of its springs, and a friction-brakewheel on the shaft having frusto-conical friction-surfaces adapted to beclamped between the inclined surfaces of the disk and fixedfriction-surface substantially as described.

7. The combination with an electric motor, its shaft, armature andeasing embodying heads having bearings for the shaft, of amagnetically-controlled friction-brake for the shaft located between thearmature and one of the heads and an electromagnet for controlling saidbrake having its coil recessed into the inner face of the head;substantially as described.

8. The combination with an electric motor,

its shaft, armature and casing embodying heads having bearings for theshaft, of a ma neticallycontrolled friction brake wheel on the shaftbetween the armature and one head, a disk loosely mounted on said head,springs for moving the disk away from the head and into engagement withthe wheel to apply the brake and an electromagnet on the inner face ofthe head for releasing the brake; substantially as described.

9. The combinationwith an electric motor, its shaft, armature and easingembodying heads having bearings for the shaft, ofamagnetically-controlled friction-brake wheel on the shaft between thearmature and one head, a relatively fixed ring on the inner side of saidWheel and means for securing the ring and head together whereby the headand frictioning the ring and head together; substantially 3 asdescribed.

ALFRED A. THRESHER.

WVitnesses:

JAMES R. WALLACE, CLAUDE W. HOSIN.

